The present invention relates to paperboard containers, and more particularly to pizza-style containers formed from a single-piece blank.
Pizza boxes are currently available in a wide variety of shapes and sizes. Many of the boxes include a square bottom panel, upright side walls, and a single lid panel that folds over the entire container. The side walls are typically formed as xe2x80x9croll-overxe2x80x9d walls that require a person to fold a first panel around a second panel and then secure the second panel into place.
These style containers have a number of drawbacks. One disadvantage concerns the use of a single lid. As background information, many pizza establishments will use hundreds of pizza at a single location during the dinner and evening hours. The boxes are often completely or partially set up ahead of time for use during these rush periods. Setting up a conventional pizza box, however, takes time and labor, and which are costs that must be accounted for in the price of the pizza. In addition, there is the difficulty encountered in forming and using these boxes, and particularly those with rolled side walls. Forming a rolled side wall box can take more than an acceptable amount of time and can also place an employee at risk for xe2x80x9ccarpal tunnel syndromexe2x80x9d or similar disorder due to the wrist motion required to form the rolled walls.
Such single lids also suffer from the tendency for the lid to fail to maintain a closed position. When a pizza box lid pops open, the pizza product inside can suffer heat loss, and, depending on the circumstances, the pizza may become inadvertently contaminated. In addition, the closure mechanisms used to engage the lid can interfere with the top of the pie, resulting in a gooey, unappetizing mess.
Thus, a need exists for an improved pizza box which is easy to set up and handle, and which includes parts which may be secured together with a minimum effort to provide a practically permanent connection therebetween. A desirable feature would be the ability to eliminate most or all of the setup time required to form the pizza. Instead, ideally, the box would be formed after a pizza is laid on it. In addition, such a container would preferably avoid rolled side walls. This would help reduce set up time and would also allow a pizza cutter to cut through the perimeter crust of a pizza pie when the pie is placed in the box, without colliding with any vertical side walls. In addition, the structure of the box should allow the manufacturer to use the smallest possible box blank sheet size and lowest fiber weight, without comprising the benefits of the container. The present invention is directed to fulfilling these needs and others, as described below.
In accordance with aspects of the present invention, various improvements are described for a container blank formed from a single piece of paperboard material. The container includes a bottom panel, first and second opposing side wall panels, and first and second opposing end wall panels. Each container further includes two top cover panels that fold over onto the container and act as lids. A first top cover panel is connected to the first end wall panel along a first hinge line.
In accordance with other aspects of the invention, at least one U-shaped cut is formed along the first hinge line. The U-shape has a closed side and an open side. The cut is oriented with the closed side extending into either of the first end wall panel or the first top cover panel. The open side is positioned along the first hinge line. As assembled, the U-shaped portion is generally perpendicular with the panel from which it was formed.
In one embodiment, a lock mechanism is described having side flaps on one top cover panel. Slots formed in the side flaps and side walls engage one another to maintain a frictional closed relationship, with portions of the side flaps being inserted inward of the side walls and portions being located outward of the side walls. In another embodiment, a lock mechanism includes a tab formed on the exposed edge of one of the top cover panels. The tab is defined between a pair of transverse edge slots. As assembled, the outer edge of the other top cover panel is wedged under the tab by passing through the transverse edge slots.
In yet another embodiment, a lock mechanism includes side extensions in one top cover panel that insert into corresponding transverse cuts in the other top cover panel. In still another embodiment, a lock mechanism includes side protrusions formed in one top cover panel that insert into slits provided in the other top cover panel.